Low-Temperature Thermocatalytic Disinfection of Escherichia coli Using Co-Doped MnOx Bimetallic Oxide Catalysts

Pathogenic Escherichia coli in wastewater necessitates energy-efficient disinfection methods. This study developed cobalt-doped manganese oxide (CoMnOx) catalysts via redox-hydrothermal synthesis for low-temperature thermocatalytic disinfection. Systematic characterization (XRD, SEM, and XPS) revealed that Co doping induced a phase transition from α-MnO2 to δ-MnO2, forming nanoflower-like structures with enhanced oxygen vacancies and optimized Mn4+/Mn3+ ratios. The optimized Co1Mn1Ox catalyst achieved complete inactivation of E. coli K-12 (5.3 lg CFU mL–1) within 1 h at 50 °C, significantly outperforming pure MnO2 and Co3O4. Mechanistic studies identified superoxide radicals (·O2–) and singlet oxygen (1O2) as the dominant reactive oxygen species (ROS), generated through lattice oxygen release and oxygen vacancy regeneration via the Mars–van Krevelen mechanism. ROS-induced membrane damage led to intracellular leakage and enzyme inactivation. The catalyst demonstrated good stability (>99.5% efficiency after four cycles) and efficacy across a relevant pH range (5.5–7.5). This work presents a sustainable strategy for efficient low-temperature water disinfection using transition metal oxide catalysts.